There is conventionally known a technology as a driver monitoring system which monitors a state of a driver who drives a vehicle; the technology captures an image of a face of a driver in a vehicle with an in-vehicle camera, detects an opening and closing state of eyelids or a direction of a sight line based on the face image, and recognizes the driver's state.
Further, when the driver's state is determined by the technology to be the state which is inappropriate for driving, an alerting technique is provided to alert the driver by using various kinds of methods. Such an alerting technique uses displaying via an in-vehicle display; speech announcing via a speaker; winding up of the seat belt; or vibrating the seat, for instance.
In addition, technologies of automated driving have been developed in recent years; even in such an automated driving, there may be arising a situation where the driver intervenes in the driving in some way. For instance, during an automated driving, a front camera or radar may fail to detect a road condition with a sufficient accuracy, causing a situation unsuitable for the automated driving.
A countermeasure responding to such a situation is known which determines whether a situation is suitable and alerts the driver upon determining the situation unsuitable for the automated driving. A technique for such alerting is disclosed which determines a wakefulness of the driver based on the opening and closing state of the eyelids and provides an appropriate alert (refer to Patent literature 1).